Without proper network redundancy, a network failure occurring within a networked automation and control infrastructure may result in a sudden and unexpected production stoppage. For example, the time, effort, and costs associated with recovery, repairs, and restarting a production line after a sudden outage may be significant for a company. Whether a plant is involved in discrete or process operations, ensuring that production runs smoothly and uninterrupted is important to the bottom line.
Network redundancy is akin to an insurance policy for industrial networks. Acting as a quick-response backup system, one of the goals of network redundancy is to mitigate the risk of unplanned outages and ensure continuity of operation by instantly responding to and reducing the effects of a point of failure anywhere along the critical data path. When one considers the direct and indirect costs of unplanned downtime, it becomes clear that making the investment in network redundancy is typically a smart strategy.
A redundant network topology, in conjunction with a redundancy protocol, is typically designed to ensure that networks continue to function in the presence of single points of failure. Network redundancy works by creating multiple data paths within a network, between any and all locations. If a cable, switch, or router suddenly fails, another pathway may be available to maintain the communication flow. Any interruptions that are caused by a failure should be as short as possible, in which reliability is increased by redundancy. A network that is based on switches or bridges will typically introduce redundant links between those switches or bridges to overcome the failure of a single link. While the use of industrial-grade network components, such as ruggedized switches and hardened or armored cables, alleviates the potential for damage or breakage of parts. A network benefits from redundancy only if the network is correctly configured with redundant paths.
An operator of an automation and control system may assume that the network is properly configured for redundancy, only to discover later that it is not when a single failure actually occurs in the network. Moreover, even if an automation and control system is properly configured, but due to a variety of reasons, network redundancy may be lost due to a variety of reasons. For example, a user may inadvertently forget to connect a cable between two devices or a cable may break after installation. Consequently, an improved method and system for verifying redundancy would be beneficial.